This invention relates to a controlled microorganism degradation process for decontaminating soil or sediments contaminated with TNT, HMX and/or RDX
Numerous land sites exist that are contaminated, and have been contaminated for decades, with the highly explosive contaminants TNT, HMX, and RDX. Many of these sites are unusable and will remain unusable until some economical process becomes available for large scale decontamination of the soil of such sites.
Prior art papers disclose laboratory experiments in microorganism biodegradation of toxic compounds such as DDT by anaerobic treatment. Significant biodegradation of DDT occurred in these experiments, but toxic metabolites of DDT remained. Remediation, as hereinafter defined was not achieved by these prior art DDT techniques.
Recent U. S. Pat. Nos. 5,660,612 and 5,660,613 disclose the remediation of soil contaminated with DDT by a method comprising repeated cycles of anaerobic composting followed aerobic composting under specific conditions of water content, temperature, redox potential and the presence of microbes capable of transforming DDT into harmless materials.
This method has been tried in attempts to decontaminate soil containing various contaminants other than DDT. While this method has been found successful with limited number of specific contaminants, it was unsuccessful for many contaminants. There was no reliable way to predict which compounds would be effectively decomposed by this method, and particularly no reason to expect that it would be successful in decontaminating soil containing explosive nitro-substituted compounds.
As described in Crawford U.S. Pat. No. 5,455,173 experiments have been done to apply microbe degradation to soil contaminated with TNT and other explosives.